Stocks on Wall Street surrendered early gains and closed broadly lower Friday after the White House said President Donald Trump would impose promised tariffs on key U.S. trading partners.

The S&P 500 fell 0.5% and the Nasdaq composite dropped 0.3%. The indexes, which had posted solid gains in morning trading, posted their first weekly loss in three weeks.

The Dow Jones Industrial Average fell 0.8%.

Trump will put in place 25% tariffs on imports from Canada and Mexico and 10% tariffs on goods from China effective Saturday. The White House provided no word on whether there would be any exemptions to the measures that could result in swift price increases to U.S. consumers.

The selling was broad, with about 75% of the stocks in the S&P 500 closing lower. Technology and energy companies accounted for a large share of the decline.

“If Trump says it’s something that could happen by tomorrow that doesn’t leave a lot of room to move,” said Sam Stovall, chief investment strategist at CFRA. “There’s just so much uncertainty associated with elevating tariffs on our three major trading partners.”

The earlier gains on Wall Street had helped shave losses from the start of the week over worries that the artificial-intelligence boom may not require as much investment as thought.